* use a RTL8139 NIC (PCI network card) with 32 pin socket and the appropriate ZIF socket adapter with flashrom. this is a low cost approach. Check, whether flashrom will recognize your flash part in this scenario.

* use a RTL8139 NIC (PCI network card) with 32 pin socket and the appropriate ZIF socket adapter with flashrom. this is a low cost approach. Check, whether flashrom will recognize your flash part in this scenario.

* [http://www.dediprog.com/SPI-flash-in-circuit-programming/SF100 Dediprog SF100]:High speed spi programmer, can be used under both windows and linux(with flashrom). See [[Dediprog SF100|SF100 Usage]] for detail description.

* [http://www.dediprog.com/SPI-flash-in-circuit-programming/SF100 Dediprog SF100]:High speed spi programmer, can be used under both windows and linux(with flashrom). See [[Dediprog SF100|SF100 Usage]] for detail description.

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* [http://dangerousprototypes.com/docs/Bus_Pirate Bus Pirate v3/v4]: SPI programmer, similar to but less expensive than the Dediprog SF100. http://flashrom.org/Bus_Pirate#Speedup

=== BIOS Savior ===

=== BIOS Savior ===

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[[Image:Top_hat_flash.JPG|thumb|right|Top Hat Flash, PCB side to flip over soldered-on PLCC.]]

[[Image:Top_hat_flash.JPG|thumb|right|Top Hat Flash, PCB side to flip over soldered-on PLCC.]]

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=== Dual flash ===

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[[File:Dual_parallel_flash.jpg|200px|thumb|right|Dual flash "pie". One for keeping working firmware image. Flash chips are selectable by a tumbler switch]]

Image:Curtain.jpeg|Alternative: with something used to support curtains.

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Revision as of 19:49, 8 August 2012

Before starting to work on coreboot support for a new mainboard and/or chipset you'll want a few development tools (both hardware and software). Not all of them are strictly required, a lot depends on your specific task and needs.

Artecgroup programmable LPC dongle

PC Engines lpc1A

This board is most useful if you are working on machines from the ALIX family, but could also be useful if you can expose an LPC header on another board.

External EPROM/Flash programmer that can program the flash chip on your motherboard

External programmers are not always necessary. Use your mainboard as a programmer instead. Boot up with a known-good image, then unplug the (DIP32, PLCC32, or DIP8) ROM chip while powered on. Reflash that secondary piece and try a reboot. Many boards allow for more than one type of flash to be programmed, but clearly are less versatile than real programmers.

use a RTL8139 NIC (PCI network card) with 32 pin socket and the appropriate ZIF socket adapter with flashrom. this is a low cost approach. Check, whether flashrom will recognize your flash part in this scenario.

Dediprog SF100:High speed spi programmer, can be used under both windows and linux(with flashrom). See SF100 Usage for detail description.

BIOS Savior

An installed BIOS Savior.

The BIOS Savior is a tool that plugs into and replaces the original mainboard Flash device. The BIOS Savior has its own Flash device and a socket for the original mainboard Flash device (PLCC or DIP versions are available). It features a switch to allow the developer to choose between which Flash device is accessed by the mainboard during read and write cycles.

This device helps to minimize the amount of hot swapping required and reduces mechanical and electrical stress on the BIOS chips.

Top Hat Flash

A similar function is achieved by the Top Hat Flash which comes at no extra cost with many Elitegroup, and some GIGABYTE and Albatron mainboards like ECS KN3 SLI2 Extreme.

As you can guess from the photo to the side, it is two plcc sockets soldered together. The upper one carries a spare BIOS chip as a fallback / failsafe secondary bootable BIOS. By means of some 'obscure' cicuitry, the additional, secondary chip is being booted from, if you manually press / stick the TOP HAT FLASH onto your primary BIOS chip on the mainboard. Sadly, this simple technique does not seem to work with other boards right away.

After bootup, it can manually be lifted off the original BIOS chip, so the original BIOS can be reflashed after a failure. The RST# pin is wired to OE# on the spare chip, otherwise it's wired 1:1. Top Hat Flash is equipped with a Winbond W39V040AP FWH. It may rely on particular circuitry on the mainboard to operate.

Top Hat Flash, PCB side to flip over soldered-on PLCC.

Dual flash

Dual flash "pie". One for keeping working firmware image. Flash chips are selectable by a tumbler switch

Since after bootup, flash mem is not accessed anymore, you can even hot plug (plug in and out while PC powered on) push pin flashes. This way you save an external EEPROM programmer and mimic the procedure of top hat flash. Make sure you do not short circuit anything, though.

PLCC32 BIOS removal tool.

DIP32 BIOS removal tool.

Push pins with cut off needles, attached to ROM chips with super glue.

More push pins on ROM chips.

Alternative: with something used to support curtains.

POST card

A POST card will save your life: it's the only output device (beside beeper) you have during the boot process. The term POST means Power On Self Test and comes from the original IBM specifications for the BIOS. Port 80 is a pre-defined I/O port to which programs can output a byte. The POST card displays the byte in hex on its 2 digit display. We use a lot of POST codes in coreboot, so if you can tell us the POST code you see, we will have some idea of what happened.

If your coreboot machine is working properly, you will see it count up from 0xd0 to 0xd9 (while it is gunzipping the kernel) and then display 0x98 (Linux idle loop). There are POST cards with ISA bus, PCI bus, USB und parallel port connectors (the latter for laptops).

Often they carry status LEDs for ISA/PCI signals such as: IRDY, BIOS-access, FRAME, OSC, PCI-CLK, RESET, 12V, -12V, 5V, -5V, 3.3V. Some cards were known to not function because the mainboard switches off the CLK on their slot after non-standard registration on PCI.

Null-modem cable

A so-called null-modem cable is used for transmitting the output from a serial coreboot (or GRUB- or Linux-) console to another computer where a terminal program (such as minicom) can be used to display/save the messages.

USB debug devices

PLX NET20DC USB Debug Device.

An alternative to a serial console may be a USB debug device. They are not so common, yet. Their advantage is higher speed than a serial console. One might hook an FPGA to it for profiling purposes or some automated checks. Accessing a USB debug device from within BIOS is not different than other USB devices, and is part of the USB standard.

Serial console software

minicom

Minicom is not just a serial terminal. It was written long before the internet existed and electronic communication was only possible with a modem to a mailbox-computer. Minicom is written with the ncurses library and provides its magic via a text interface. Other than logging, it provides z-modem up- and download-capability.

CuteCom

This is an easy to use serial-terminal-program which is even able to write all communication into a log-file. It needs a computer with installed Qt-libs.